Advertisements
Advertisements
Question
- Assertion (A): For the radiation of a frequency greater than the threshold frequency, the photoelectric current is proportional to the intensity of the radiation.
- Reason (R): Greater the number of energy quanta available, the greater the number of electrons absorbing the energy quanta and the greater the number of electrons coming out of the metal.
Options
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
Advertisements
Solution
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Explanation:
When the frequency of the incident radiation exceeds the threshold frequency, the photoelectric current is proportional to the intensity of the radiation. As a result, the assertion is correct. As the intensity rises, so does the number of energy quanta accessible. By absorbing more energy quanta, a bigger number of electrons are emitted. A higher number of electrons equals a higher current. As a result, the photoelectric current becomes proportional to radiation intensity. So, the reason is also true, and it adequately explains the assumption.
APPEARS IN
RELATED QUESTIONS
Light of intensity 10−5 W m−2 falls on a sodium photo-cell of surface area 2 cm2. Assuming that the top 5 layers of sodium absorb the incident energy, estimate time required for photoelectric emission in the wave-picture of radiation. The work function for the metal is given to be about 2 eV. What is the implication of your answer?
Can we find the mass of a photon by the definition p = mv?
Light of wavelength λ falls on a metal with work-function hc/λ0. Photoelectric effect will take place only if
When stopping potential is applied in an experiment on photoelectric effect, no photoelectric is observed. This means that
A totally reflecting, small plane mirror placed horizontally faces a parallel beam of light, as shown in the figure. The mass of the mirror is 20 g. Assume that there is no absorption in the lens and that 30% of the light emitted by the source goes through the lens. Find the power of the source needed to support the weight of the mirror.
(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
Define the term: threshold frequency
In the case of photoelectric effect experiment, explain the following facts, giving reasons.
The photoelectric current increases with increase of intensity of incident light.
Consider a 20 W bulb emitting light of wavelength 5000 Å and shining on a metal surface kept at a distance 2 m. Assume that the metal surface has work function of 2 eV and that each atom on the metal surface can be treated as a circular disk of radius 1.5 Å.
- Estimate no. of photons emitted by the bulb per second. [Assume no other losses]
- Will there be photoelectric emission?
- How much time would be required by the atomic disk to receive energy equal to work function (2 eV)?
- How many photons would atomic disk receive within time duration calculated in (iii) above?
- Can you explain how photoelectric effect was observed instantaneously?
How would the stopping potential for a given photosensitive surface change if the frequency of the incident radiation were increased? Justify your answer.
The figure shows a plot of stopping potential (V0) versus `1/lambda`, where λ is the wavelength of the radiation causing photoelectric emission from a surface. The slope of the line is equal to ______.
